A power distribution system may receive electrical power from any of a variety of sources, including fossil fuels, wind, water, and solar. Some power distribution systems bring power from the source to the load; others distribute the power to a power grid, which delivers the power to the end use.
In solar power distribution systems, electricity may be generated by photovoltaic (PV), or solar, panels (modules) wired together in series. A series connection of modules is known as a “string”. In some systems, particularly those of larger scale (e.g., more than two strings), the strings are introduced to a “combiner” or “combiner box”, where the input string cables may be combined into one or more output cables. In systems having multiple combiners, the output of each combiner may be introduced to a “re-combiner box” to be combined into one or more output cables. Combiner boxes and re-combiner boxes may be similar in structure and thus in this disclosure, “combiner” and “combiner box” will be used with the understanding that the related description applies equally to a “re-combiner” or “re-combiner box”.
A combiner box may contain a variety of mechanical, electrical, and electronic components. For example, a combiner box may house input fuses for corresponding input strings, bus bars, terminals for combining the inputs after the fuses, a DC disconnect, a surge protector and other overcurrent protection devices, current monitoring sensors, arc-fault sensors, and rapid-disconnect contacts. Pre-terminated input whips may be provided to connect string cables to the combiner box via the whips instead of hard-wiring to fuse terminals inside the box.
Combiner boxes may be installed outdoors, often near the PV panels, where they are exposed to environmental considerations such as rain, ultraviolet radiation, humidity, animals, etc. They may be mounted on a roof, wall, or bolted to the floor. In any installation, it is desirable for the combiner box to be durable, wieldy, and versatile.